Jaw grip force adjustment system for offset and 90 degree pulling heads

ABSTRACT

The invention provides a pulling head, a jaw gripping assembly, and an adjustment assembly. The pulling head has a frame having first and second ends with the first end being configured to receive a stem of a fastener therein. The jaw gripping assembly is generally positioned within the frame. The adjustment assembly is operatively associated with at least one of the frame and the jaw gripping assembly. Manipulation of the adjustment assembly in a first manner moves the jaw gripping assembly closer to the first end of the frame in order to minimize an amount of jaw grip force generated by the jaw gripping assembly, while manipulation of the adjustment assembly in a second manner moves the jaw gripping assembly distal to the first end of the frame in order to maximize an amount of jaw grip force generated by the jaw gripping assembly.

CROSS-REFERENCE AND INCORPORATION BY REFERENCE

This application is a continuation of U.S. patent application Ser. No.13/330,187, filed on Dec. 19, 2011, and entitled “JAW GRIP FORCEADJUSTMENT SYSTEM FOR OFFSET AND 90 DEGREE PULLING HEADS”. U.S. patentapplication Ser. No. 13/330,187 is hereby incorporated by reference inits entirety.

FIELD OF THE INVENTION

This invention is generally directed to a jaw grip force adjustmentsystem for offset pulling heads. It is also directed to an improved 360degree swivel system for offset and right angle pulling heads.

BACKGROUND OF THE INVENTION

Aerospace blind fasteners are widely used in aircraft manufacturing.There are many different types and sizes that are used, based on thematerial or strength characteristics required. These blind fasteners aretypically comprised of a sleeve, a stem and some type of lockingmechanism. The stem of a fastener is gripped by jaws inside of a pullinghead, while the sleeve of the fastener is biased against the front ofthe pulling head housing. The fasteners are installed by placing them ina hole prepared in the aircraft structure and pulling on a protrudingstem accessible on the non-blind side.

The stem typically features a series of annular grooves, calledserrations, which are to be engaged by the jaws of the pulling head usedto install them. During installation, the stem is pulled away from thestructure. While applying this pulling load to the stem, some type ofdeformation occurs on the blind side of the structure or inside of thehole, depending on the particular type of fastener used. Toward the endof the fastener installation cycle, a locking ring is deformed in placewhich locks the fastener in an installed position and the stem separatesfrom the fastener.

The pulling heads generally used to install blind fasteners arecomprised of a draw-bolt containing a set of jaws, and a housing thatsets the locking mechanism and provides support to the fastener duringinstallation.

In aerospace blind fastening systems, the gripping force provided by thejaws is very important for proper fastener installation—too little forcecauses slippage leading to installation failures and too much forcemakes it difficult to use the tool, which also causes productivity andtool wear issues. Straight pulling heads can easily be adjusted for theamount of grip the jaws provide, however offset or 90 degree pullingheads presently on the market do not provide adjustments for the grip ofthe jaws. For instance, the Cherry Aerospace Single Jaw Offset PullingHead H781-456 is a popular tool with the aircraft manufacturers becauseof its low profile and its ability to reach into very tight areas. Thistool, however, does not have a jaw grip adjustment so it sometimes hasproblems installing smaller diameter fasteners.

In order to address this issue, complicated set-up processes have beendevised to try and address the slippage issue. However, despite theforegoing, the underlying problem coming from lack of proper adjustmentstill exists.

The present invention overcomes problems presented in the prior art andprovides additional advantages over the prior art. More particularly,the present invention has been developed to address stem slippage issuesinherent to the offset and 90 degree pulling heads, which has limitedtheir usage. Such advantages will become clear upon a reading of theattached specification in combination with a study of the drawings.

SUMMARY OF THE INVENTION

Briefly, the present invention discloses an adjustment system configuredto adjust a jaw gripping force of a pulling head connected to a powertool. The adjustment system has a locking nut configured to bethreadedly attached to the pulling head. The locking nut defines anaperture which extends therethrough. The adjustment system further has aframe adaptor which is configured to be at least partially positionedwithin the aperture of the locking nut. The frame adaptor is furtherconfigured to receive a portion of the pulling head and a piston of thepower tool within an aperture thereof, with the portion and the pistonengaging one another within the aperture of the frame adaptor. Theportion of the pulling head is operatively associated with a jaw of thepulling head. The adjustment system further has an adjustment nut whichis configured to be threadedly attached to the frame adaptor.

In use, when the locking nut is in an unlocked position, the adjustmentnut can be rotated in a counterclockwise manner in order to strengthenthe jaw gripping force of the pulling head by causing the portion of thepulling head to move toward the power tool. Alternatively, when thelocking nut is in an unlocked position, the adjustment nut can berotated in a clockwise manner in order to weaken the jaw gripping forceof the pulling head by causing the portion of the pulling head to moveaway from the power tool.

BRIEF DESCRIPTION OF THE DRAWINGS

The organization and manner of the structure and operation of theinvention, together with further objects and advantages thereof, maybest be understood by reference to the following description, taken inconnection with the accompanying drawings, wherein like referencenumerals identify like elements in which:

FIG. 1 is a perspective view of a power tool, an adjustment assembly anda pulling head in an assembled manner;

FIG. 2 is an exploded perspective view of a power tool, an adjustmentassembly and a pulling head in an unassembled manner;

FIG. 3 is a cross-sectional view of a prior art single jaw offsetpulling head;

FIG. 4 is an exploded perspective view of the prior art single jawoffset pulling head shown in FIG. 3 and the adjustment assembly;

FIG. 5 is an exploded perspective view of the adjustment assembly,without the jam nut;

FIG. 6 is a perspective view of the adjustment assembly, without the jamnut, shown in FIG. 5;

FIGS. 7-14 are perspective and side views of the power tool, theadjustment assembly and the pulling head being operatively associatedwith one another and illustrating the steps for adjusting a jaw grippingforce of the pulling head; and

FIGS. 15 and 16 are perspective views of the power tool, the adjustmentassembly and the pulling head being operatively associated with oneanother and illustrating the steps for adjusting an angular portion ofthe pulling head relative to the power tool.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

While the invention may be susceptible to embodiment in different forms,there is shown in the drawings, and herein will be described in detail,a specific embodiment with the understanding that the present disclosureis to be considered an exemplification of the principles of theinvention, and is not intended to limit the invention to that asillustrated and described herein.

The invention provides for a jaw grip force adjustment system 100, whichis best illustrated in FIGS. 2 and 4. The jaw grip force adjustmentsystem 100 further acts as an adaptor from a power tool 200, such as ariveter, to a pulling head 300, which is preferably an offset pullinghead, as illustrated in FIG. 3, or a 90 degree puling head (not shown).

FIGS. 1 and 2 illustrate a typical power tool 200, such as a riveter.The power tool 200 is a known device and, therefore, will not bedescribed in any detail, except to describe and illustrate parts of thepower tool 200 that interact with the jaw grip force adjustment system100 and the pulling head 300. The power tool 200 includes a piston 202which has an outer threaded surface 204. The power tool 200 furtherincludes a head 206 which has an inner threaded surface 208. The innerthreaded surface 208 defines an inner diameter of the head 206 which islarger than an outer diameter defined by the outer threaded surface 204of the piston 202.

FIGS. 3 and 4 illustrate a prior art single jaw offset pulling head 300.Specifically, FIG. 3 provides a cross-sectional view, while FIG. 4provides an exploded perspective view. As shown, the device provides asingle jaw 302 which is biased by a spring 304 inside a drawbolt saddle306. The jaw 302 has an angled surface 308 which engages a correspondingangled surface 310 on a drawbolt 312. The drawbolt 312 is disposedgenerally in a frame 314 of the pulling head 300, and a drawbolt adaptor316 is threadably engaged with the drawbolt 312. The drawbolt adaptor316 has first and second opposite ends 318, 319. The first end 318 ofthe drawbolt adaptor 316 is threadably engaged with the drawbolt 312.The drawbolt adaptor 316 further includes a recess (not shown) at thesecond end 319 which defines a threaded inner surface (not shown) of thedrawbolt adaptor 316.

In addition, the pulling head 300 includes a dowel pin 322 for securingthe drawbolt saddle 306 to the drawbolt 312, a roll pin 324 forfacilitating sliding of the drawbolt 312 relative to the frame 314, aroll pin 326 for anchoring the drawbolt saddle 306 to the drawbolt 312,and a guard 328 for enclosing an otherwise exposed portion of thepulling head 300. The roll pin 324 preferably extends through thedrawbolt 312 such that its ends extend beyond the drawbolt 312. A frontend 330 of the frame 314 of the pulling head 300 has an opening 332 forreceiving a stem of a fastener (not shown) that is desired to beinstalled, such that the stem can be gripped by the jaw 302 inside thepulling head 300. Sides 334 of the frame 314 of the pulling head 300have slots 336 for receiving the ends of the roll pin 324 in order tofacilitate sliding of the drawbolt 312 relative to the frame 314 and toallow for visual inspection of the roll pin 324, and thus the locationof the drawbolt 312, relative to the frame 314. At least one of thesides 334 of the frame 314 also further preferably includes adjustmentmarks 338 above and/or below the slots 336. These adjustment marks 338are provided at a location along the slots 336 where full jaw grippingforce is achieved, as will be discussed in further detail hereinbelowduring a description of the operation. An outer threaded surface 342 ofthe frame 314 of the pulling head 300 is defined proximate a rear end340 of the frame 314 of the pulling head 300.

The jaw grip force adjustment system 100 is best illustrated in FIGS. 2and 4-6. The adjustment system 100 comprises a frame adaptor 102, alocking nut 104, an adjustment nut 106, and a jam nut 108.

The frame adaptor 102 is best illustrated in FIG. 5. The frame adaptor102 is generally cylindrical in configuration and extends from a firstend 110 to a second end 112. The frame adaptor 102 has an aperture 113provided therethrough which extends from the first end 110 to the secondend 112. The aperture 113 defines a generally cylindrical inner surface114, preferably of a constant diameter. The frame adaptor 102 furtherdefines a generally cylindrical outer surface 116 which extends from thefirst end 110 to the second end 112. The generally cylindrical outersurface 116 has a first diameter portion 118 proximate to the first end110 and a second diameter portion 120 proximate to said second end 112.The first diameter portion 118 is larger than the second diameterportion 120 such that a shoulder 121 is defined between the first andsecond diameter portions 118, 120. The second diameter portion 120provides a thread relief portion 120 a provided proximate to theshoulder 121 and a threaded portion 120 b from the thread relief portion120 a to the second end 112.

The locking nut 104 is best illustrated in FIG. 5. The locking nut 104is generally cylindrical in configuration and extends from a first end122 to a second end 124. The locking nut 104 has an aperture 125provided therethrough which extends from the first end 122 to the secondend 124. The aperture 125 defines a generally cylindrical inner surface126. The generally cylindrical inner surface 126 has first, second andthird diameter portions 128, 130, 132. The first diameter portion 128 isprovided proximate to the first end 122, the third diameter portion 132is provided proximate to the second end 124, and the second diameterportion 130 is provided between the first and third diameter portions128, 132. The first and second diameter portions 128, 130 haveapproximately the same diameter, but the second diameter portion 130 isthreaded. The third diameter portion 132 has a diameter which is lessthan the diameter of the second diameter portion 130, such that ashoulder 134 is defined between the second and third diameter portions130, 132.

The locking nut 104 further defines a generally cylindrical outersurface 136 which extends from the first end 122 to the second end 124.The generally cylindrical outer surface 136 has first and seconddiameter portions 138, 140. The first diameter portion 138 is providedproximate to the first end 122 and the second diameter portion 140 isprovided proximate to the second end 124. The first diameter portion 138has a diameter which is larger than a diameter of the second diameterportion 140, such that a shoulder 142 is defined between the first andsecond diameter portions 138, 140. The first diameter portion 138preferably is not smooth, but rather is configured in such a manner asto aid a user to grip the first diameter portion 138 of the generallycylindrical outer surface 136 of the locking nut 104.

The adjustment nut 106 is best illustrated in FIG. 5. The adjustment nut106 is generally cylindrical in configuration and extends from a firstend 144 to a second end 146. The adjustment nut 106 has an aperture 147provided therethrough which extends from the first end 144 to the secondend 146. The aperture 147 defines a generally cylindrical inner surface148. The generally cylindrical inner surface 148 has first and seconddiameter portions 150, 152. The first diameter portion 150 is providedproximate to the first end 144, and the second diameter portion 152 isprovided proximate to the second end 146. The first and second diameterportions 150, 152 have approximately the same diameter, but the seconddiameter portion 152 is threaded.

The adjustment nut 106 further defines a generally cylindrical outersurface 154 which extends from the first end 144 to the second end 146.The generally cylindrical outer surface 154 preferably has a constantdiameter from the first end 144 to the second end 146. The generallycylindrical outer surface 154 preferably is not smooth, but rather isconfigured in such a manner as to aid a user to grip the generallycylindrical outer surface 154 of the adjustment nut 104.

The jam nut 108 is best illustrated in FIG. 4. The jam nut 108 extendsfrom a first end 156 to a second end 158. The jam nut 108 has anaperture 159 provided therethrough which extends from the first end 156to the second end 158. The aperture 159 defines a generally cylindricalinner surface 160. The generally cylindrical inner surface 160 ispreferably threaded. The jam nut 108 further defines an outer surface162 which extends from the first end 156 to the second end 158. Theouter surface 162 is preferably formed in a hex shape such that it canbe gripped and rotated by an appropriate tool, such as a wrench. It isto be understood that the outer surface 162 of the jam nut 108 could beformed in any other appropriate configuration.

The assembly of the adjustment system 100 is best illustrated in FIGS. 1and 6. The second end 112 of the frame adaptor 102 is inserted into theaperture 125 of the locking nut 104 from the first end 122 of thelocking nut 104 until the shoulder 121 of the generally outercylindrical surface 116 of the frame adaptor 102 abuts against theshoulder 134 of the generally inner cylindrical surface 126 of thelocking nut 104. With the shoulders 121, 134 abutting one another, thesecond end 112 of the frame adaptor 102, the threaded portion 120 b ofthe second diameter portion 120, and a portion of the thread relief 120a of the second diameter portion 120 of the generally cylindrical outersurface 116 of the frame adaptor 102 extend beyond the second end 124 ofthe locking nut 104. The frame adaptor 102 and the locking nut 104 arecapable of rotating relative to one another.

The second end 112 of the frame adaptor 102 is then inserted into theaperture 147 of the adjustment nut 106 from the first end 144 of theadjustment nut 106 until the threaded portion 120 b of the seconddiameter portion 120 of the generally cylindrical outer surface 116 ofthe frame adaptor 102 comes into contact with the threaded seconddiameter portion 152 of the generally cylindrical inner surface 148 ofthe adjustment nut 106. The frame adaptor 102 and the adjustment nut 106are then threadedly engaged with one another until the first end 144 ofthe adjustment nut 106 is tightened against the thread relief 120 a. Theend of the frame adaptor 102 may be provided with flats 119 which areused to hold the frame adaptor 102 while tightening the adjustment nut106. A high strength thread locker is preferably used to permanentlylock the adjustment nut 106 to the frame adaptor 102. Alternatively,deforming the thread or spot welding may achieve the same goal. With theadjustment nut 106 permanently locked to the frame adaptor 102, thefirst diameter portion 150 of the generally cylindrical inner surface148 of the adjustment nut 106 is positioned around the second diameterportion 140 of the generally cylindrical outer surface 136 of thelocking nut 104. The second end 112 of the frame adaptor 102 and aportion of the threaded portion 120 b of the second diameter portion 120of the generally cylindrical outer surface 116 of the frame adaptor 102also extend beyond the second end 146 of the adjustment nut 106.

The second end 112 of the frame adaptor 102 is then inserted into theaperture 159 of the jam nut 108 from the first end 156 of the jam nut108 and the threaded portion 120 b of the second diameter portion 120 ofthe generally cylindrical outer surface 116 of the frame adaptor 102 isthreadedly engaged with the jam nut 108 until, at least, the second end112 of the frame adaptor 102 extends beyond the second end 158 of thejam nut 108.

The adjustment system 100 is then connected to the pulling head 300 andthe jam nut 108 is threaded toward the adjustment nut 106. In order toconnect the adjustment system 100 to the pulling head 300, the outerthreaded surface 342 of the frame 314 of the pulling head 300 and thethreaded second diameter portion 130 of the generally cylindrical innersurface 126 of the lock nut 104 are threadedly engaged with one another.

The assembly of the adjustment system 100 and the pulling head 300 isthen threaded onto the power tool 200. In order to connect the assemblyto the power tool 200, the threaded portion 120 b of the second diameterportion 120 of the generally cylindrical outer surface 116 of the frameadaptor 102 and the inner threaded surface 208 of the head 206 of thepower tool 200 are threadedly engaged with one another, and the threadedinner surface (not shown) of the drawbolt adaptor 316 and the outerthreaded surface 204 of the piston 202 of the power tool 200 arethreadedly engaged with one another. Once these two threaded engagementsare made, the jam nut 108 is threaded against the head 206 of the powertool 200.

In use, a stem of a fastener (not shown) that is desired to be set isinserted into the opening 332 which is provided in the front end 330 ofthe frame 314 of the pulling head 300. While the jaw 302 is springbiased closed by the spring 304, when the stem is inserted into theopening 332, the stem pushes the jaw 302 open and the jaw 302 springsback against the stem and becomes seated against the stem. Then, thepower tool 200 is actuated causing the piston 202 to be pulled back,thereby pulling on the drawbolt adaptor 316. Pulling on the drawboltadaptor 316 causes the drawbolt 312 and the drawbolt saddle 306 to moveback in the frame 314 (i.e., in a direction away from the opening 332 inthe front end 330 of the frame 314). Due to the fact that the jaw 302has an angled surface 308 which engages a corresponding angled surface310 on the drawbolt 312, movement of the drawbolt 312 in a directionaway from the opening 332 in the front end 330 of the frame 314 causesthe jaw 302 to grip and effectively lock on the stem of the fastener,whereby further actuation of the power tool 200 eventually causes thestem to be pulled sufficiently such that the fastener sets and the stembreaks off.

As explained above, with the adjustment system 100 connected to both thepower tool 200 and to the pulling head 300, the adjustment system 100may be manipulated in order to adjust the jaw gripping force dependingon the size of the fastener to be set, as illustrated in FIGS. 7-14.More specifically, the adjustment system 100 allows for adjustmentbetween the two main components of the pulling head 300, namely, thedrawbolt 312 and the frame 314. Since there is full adjustment, nospecial assembly instructions need to be followed by users when thepulling head 300 is installed to the power tool 200.

For smaller sized fasteners, for instance those having a diameter of ⅛inch or less, a stronger jaw gripping force is required. For thesesmaller sized fasteners, the jaw gripping force can be appropriatelyadjusted by first unlocking and threading the jam nut 108 away (in acounter-clockwise direction) from the head 206 of the power tool 200, asillustrated in FIG. 7.

The locking nut 104 is then unlocked by turning the locking nut 104 (ina clockwise direction) relative to the outer threaded surface 342 of therear end 340 of the frame 314 of the pulling head 300, as illustrated inFIG. 8. Preferably, the locking nut 104 should not be rotated more than½ turn.

Next, while holding the frame 314 of the pulling head 300 stationary,the adjustment nut 106 is rotated counterclockwise, as illustrated inFIGS. 9 and 10. This counterclockwise rotation of the adjustment nut 106causes the drawbolt 312 to move rearward within the frame 314 of thepulling head 300, thus causing the roll pin 324 to move rearward withinthe slots 336 of the sides 334 of the frame 314 and causing the drawboltadaptor 316 to move away from the front end 330 of the frame 314. Themore space S_(max) which is provided between a front end of the drawboltadaptor 316 and the front end 330 of the frame 314, the more the jaw 302can close, thereby generating more gripping force. Maximum grippingforce is obtained when the roll pin 324 is positioned in the slots 336in alignment with the adjustment marks 338. Once the maximum grippingforce is achieved, further counter-clockwise of the adjustment nut 106,such that the roll pin 324 is positioned in the slots 336 beyond theadjustment marks 338 and distal from the front end 330 of the frame 314,will not increase the jaw grip force any further, but it will decreasethe stroke significantly.

With the jaw gripping force set as desired, the frame 314 is held in thedesired angular position (as will be discussed in further detailhereinbelow) and the locking nut 104 is rotated counter-clockwise tohand tight in order to lock the adjustment, as illustrated in FIG. 11.

The jam nut 108 can then be rotated clockwise against the head 206 ofthe power tool 200 in order to lock the pulling head 300 in place, asillustrated in FIG. 12.

For larger sized fasteners, for instance those having a diameter of 5/32inch or more, a weaker jaw gripping force is required. For these largersized fasteners, the jaw gripping force can be appropriately adjusted byfirst unlocking and threading the jam nut 108 away (in acounter-clockwise direction) from the head 206 of the power tool 200, asillustrated in FIG. 7.

The locking nut 104 is then unlocked by turning the locking nut 104 (ina clockwise direction) relative to the outer threaded surface 342 of therear end 340 of the frame 314 of the pulling head 300, as illustrated inFIG. 8. Preferably, the locking nut 104 should not be rotated more than½ turn.

Next, while holding the frame 314 of the pulling head 300 stationary,the adjustment nut 106 is rotated clockwise, as illustrated in FIGS. 13and 14. This clockwise rotation of the adjustment nut 106 causes thedrawbolt 312 to move forward within the frame 314 of the pulling head300, thus causing the roll pin 324 to move forward within the slots 336of the sides 334 of the frame 314 and causing the drawbolt adaptor 316to move toward the front end 330 of the frame 314. The less spaceS_(min) which is provided between a front end of the drawbolt adaptor316 and the front end 330 of the frame 314, the less the jaw 302 canclose, thereby generating less gripping force. The minimum grippingforce is obtained when the roll pin 324 is positioned in the slots 336in general abutment with a forward end of the slots 336, which isprovided proximal to the front end 330 of the frame 314.

With the jaw gripping force set as desired, the frame 314 is held in thedesired angular position (as will be discussed in further detailhereinbelow) and the locking nut 104 is rotated counter-clockwise tohand tight in order to lock the adjustment, as illustrated in FIG. 11.

The jam nut 108 can then be rotated clockwise against the head 206 ofthe power tool 200 in order to lock the pulling head 300 in place, asillustrated in FIG. 12.

Thus, the process for adjusting the jaw gripping force is identical forstrengthening or weakening the jaw gripping force, except for thedirection in which the adjustment nut 106 is rotated, namelycounter-clockwise (as illustrated in FIGS. 9 and 10) to strengthen thejaw gripping force or clockwise (as illustrated in FIGS. 13 and 14) toweaken the jaw gripping force.

As illustrated in FIGS. 7, 15 and 16, the adjustment system 100 alsoallows for 360 degree adjustment of an angular position of the pullinghead 300 relative to the power tool 200. This 360 degree adjustment canoccur without disengaging the drawbolt 312 from the piston 202 of thepower tool 200, as is required by current designs. The potential dangerwith these current designs is that disengaging the drawbolt 312 whilecontrolling the orientation of the pulling head 300 can cause the piston202 of the power tool 200 to break, thereby disabling the power tool200. Such a break of the piston 202 can also be expensive to fix.

In order to adjust the angular position of the pulling head 300 relativeto the power tool 200, the locking nut 104 is unlocked, preferably by nomore than ½ turn, as illustrated in FIG. 7; the jam nut 108 is notmanipulated. The pulling head 300 is then turned until the correctangular position has been reached, as illustrated in FIG. 15. Thelocking nut is then rotated counter-clockwise to hand tight in order tolock the adjustment, as illustrated in FIG. 16.

Thus, as discussed, the adjustment system 100 of the present inventionprovides a number of advantages over the prior art including the abilityto operate both the locking nut 104 and the adjustment nut 106 by hand,and that adjustment can be made on the fly during use of the pullinghead 300 (not only at set-up like current pulling heads).

While a preferred embodiment of the present invention is shown anddescribed, it is envisioned that those skilled in the art may devisevarious modifications of the present invention without departing fromthe spirit and scope of the invention.

The invention claimed is:
 1. A combination comprising: a pulling headhaving a frame having first and second ends and a jaw gripping assemblywhich is generally positioned within said frame; said first end of saidframe being configured to receive a stem of a fastener therein; and anadjustment assembly which is operatively associated with at least one ofsaid frame and said jaw gripping assembly, said adjustment assemblybeing configured to be manipulated in a first manner in order to movesaid jaw gripping assembly closer to said first end of said frame inorder to minimize an amount of jaw grip force generated by said jawgripping assembly, said adjustment assembly being configured to bemanipulated in a second manner in order to move said jaw grippingassembly distal to said first end of said frame in order to maximize anamount of jaw grip force generated by said jaw gripping assembly.
 2. Amethod of adjusting a jaw gripping force of a pulling head, said methodcomprising: a) providing a power tool having a piston and a head; b)providing a pulling head having a frame having first and second ends anda jaw gripping assembly which is generally positioned within said frame;said first end of said frame being configured to receive a stem of afastener therein, said piston of said power tool being operativelyassociated with said jaw gripping assembly of said pulling head; and c)providing an adjustment assembly which is operatively associated with atleast one of said frame and said jaw gripping assembly; d) manipulatingsaid adjustment assembly in a first manner to move said jaw grippingassembly closer to said first end of said frame in order to minimize anamount of jaw grip force generated by said jaw gripping assembly; and e)manipulating said adjustment assembly in a second manner to move saidjaw gripping assembly distal to said first end of said frame in order tomaximize an amount of jaw grip force generated by said jaw grippingassembly.